Prism in Glasses: What Is It and How Does It Impact Vision?

Prism correction is an optical element added to your glasses to reduce or eliminate double vision, also known as diplopia.

In the video below, Sheena Taff discusses what you need to know before getting prism put in your glasses.

If you don’t like the video or want more information, continue reading.

Do you need prism in your glasses?

When experiencing double vision with both eyes open, the images entering your eyes are falling in two different places on your retinas. Unfortunately, this causes double vision. Prism in glasses helps re-align the images at the same point in the back of both eyes. Doing so allows you to fuse both images together to create one, single image.

Fortunately for you, your optometrist or ophthalmologist can prescribe you prism to aid in managing your double vision. Depending on your need, prism is measured and prescribed in diopters, ranging anywhere from 0.5 diopters up all the way up to the extreme 40 diopters (although I have yet to see it prescribed that high)!

Prism base can be set up, down, in or out, and works to shifts the image location to trick your brain into thinking the images are in the same place, thus creating one clear image. Also, prism can be placed all in one lens or split between two lenses. Both achieve the same result and allow your eyes to work together in unison.

Causes of double vision

Double vision can be caused by a muscle imbalance in your extraocular muscles, such as an eye turn (i.e strabismus) or a disproportion in the prescription required in each eye.

Other causes of double vision that can benefit from prism include a stroke or concussion-related brain injury.

This is what fresnel prism looks like before being put on your glasses.

Fresnel prism

Lastly, your eye doctor may suggest a trial with fresnel prism before prescribing it for your glasses. Fresnel prism is a press on vinyl sticker that easily adheres to an existing pair of glasses. Once applied, it can be removed without damage to your current glasses.

Fresnel prism often gives instant relief of double vision and is an opportunity to try the benefits of prism without risk or major cost.

Sheena Taff is an optician in beautiful British Columbia Canada.
You could say she was born with optical genes, as she is the child of two opticians.
She took the reigns of their independent optical practice 7 years ago and have since found her calling in all things optical.
She's devoted to the science and technical knowledge that goes into creating a premium pair of eyeglasses and loves that she has the opportunity to create glasses from start to finish!
She has a passion for fashion, beauty and design.
Everyday she has the pleasure of opening the eyes of eyeglass wearers to the joys of style expression through eyewear, helping them look and see their best!